The field of invention relates generally to computer processor architecture, and, more specifically, to platform security.
Low level hardware and firmware attacks are becoming more and more prevalent in computer systems and could lead to permanent denial of service (PDOS). PDOS is a big concern for data center systems that could lead to heavy financial losses and potentially even loss of life in cases where systems are deployed in critical infrastructures.
The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:
of the invention;
In the following description, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known circuits, structures and techniques have not been shown in detail in order not to obscure the understanding of this description.
References in the specification to “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.
As noted, a computer can get compromised and lead to PDOS scenarios. When such a scenario occurs, embodiments detailed herein provide hooks to detect that a corruption has occurred and recover to a known good state. Typically, recovery is automatic, local, and fast (e.g., in a matter of seconds or minutes) without human intervention. The recovery mechanism may also be extended to the operating system (OS) and application layers by making use of remote authenticated writes to special protected partitions. Protected partitions house recovery images. In case of an attack, an active corrupt image is erased and restored with a known good recovery image from the protected partition. During runtime, embodiments detailed herein provide active filtering capabilities on buses like serial peripheral interface (SPI) that provide access to non-volatile storage to protect against known attacks that could lead to corruption of in the non-volatile (e.g., FLASH) storage of critical components like SPI flash storage, power supply firmware storage, DIMM SPD storage, Hot-Swap-Back-Plane (HSBP) storage, etc.
The hardware processors (CPU 0101 and CPU 1103) communicate with security circuitry 105 using one or more buses. An exemplary bus is a system management bus (SMBUS). Security circuitry 105 is responsible for reset/boot sequencing, providing some monitoring and filtering capabilities, and access to I/O hub flash 123 and baseband management controller (BMC) flash 121. Note that one or more of the components illustrated as being a part of the security circuitry 105 may be outside of the circuitry footprint.
A BMC 119 monitors the physical state of the platform and communicates with external devices. The BMC 119 may go by other names including, but not limited to, management module, advanced management module, advanced systems management processor, and integrated management module. The security circuitry 105 also provides hardware acceleration support to the CPU for cryptographic functions 109 including hashing functions (e.g., SHA, MDS, etc.) and encryption (e.g., AES, etc.).
The BMC 119 accesses several other components like digital voltage regulator 117, hot swap backplane (HSBP) 115, power supply unit 113, etc. via SMBUS. These buses are routed through the security circuitry 105 allowing it to monitor and filter the SMBUS transactions to these devices during normal boot and runtime. For example, a monitor circuit 131 provides this functionality. There are several ways to monitor and filter transactions including white listing of commands that are acceptable to be sent from/to the BMC 119, or blacklisting those that are not.
A core complex programmable logic device (CPLD) 107 controls reset and timing sequences for the platform. In some embodiments, the core CPLD 107 has different reset and timing sequences for pre-boot and boot sequences. In some embodiments, core CPLD 107 requires in-field updates. The security circuitry 105 provides a secure mechanism to fetch the latest updated image from the FLASH (123 or 121) via a serial peripheral interface (SPI) boot capability.
A selector (e.g., a mux) 111 is used to select which flash 121 or 123 to talk to over SPI. I/O hub selector 127 and BMC selector 129 are used to select between the security circuitry 105 and the I/O hub 125 or BMC 119 respectively. As such, security circuitry 105 has access to the I/O hub flash 123 and the BMC flash 123 via a selector 111.
The security circuitry 105 gains access to the flash during a pre-boot mode and I/O hub 125 and the BMC 119 have access to their respective flash devices during normal boot. The SPI bus at the input of the flash devices is routed to the security circuitry 105 allowing for monitoring filtering of SPI flash transactions during normal boot when the I/O hub 125 and BMC 119 are operational and issuing transactions. For example, the security circuitry 105 may use address based filtering or maintain a list of transactions (commands) that are okay (a white list). When a malicious transaction is detected, the corresponding chip-select is de-asserted by the security circuitry 105 to prevent the transaction for proceeding. Typically, the monitor circuit 131 performs these functions.
The security circuitry 105 includes, or has access to, memory 135 which stores one or more keys and/or integrity check patterns.
In summary, the security circuitry 105 monitors and gains control over components that have non-volatile storage to house firmware pieces required for the proper functioning of these devices. Corruption in any of these components could lead to a permanent denial service. The security circuitry 105 also controls the assertion of come critical signals and hardware straps required to be driven in order to enable booting in a pre-boot environment while keeping the other devices inactive.
A secure pre-boot is performed at 403. The pre-boot is a trusted mode of operation in which firmware verification, update and recovery operations occur. In pre-boot only one CPU is powered up and other external devices (e.g., BMC 119 and/or I/O hub 125) are kept at complete rest. Typically, the core CPLD 107 with the security circuitry 105 drives some of the critical signals that would otherwise be driven by the I/O hub to trigger the platform power up sequence.
In some embodiments, an explicit boot progress monitoring is performed. For example, watchdog timers implemented within the security circuitry 105 are used to monitor boot process. Different sections of the boot firmware rendezvous with the security circuitry 105 at different boot stages to record successfully booting to the particular stage before the watchdog timer expires. This is referred to herein as a checkpoint. A checkpoint is made at 404 in some embodiments. If the checkpoint fails, then secure pre-boot operations are performed at 403. If the checkpoint is successful, then pre-boot is complete.
After the pre-boot is complete (e.g., secure boot or recovery is complete), security circuitry removes the direct current (DC) power to the CPU at 405. As such, the CPU, BMC 119, and I/O hub 125 are all without a context. In some embodiments, the security circuitry 105 is up during this transition.
After DC power down, security circuitry restores the DC power and the CPU(s), I/O hub 125, and BMC 119 are enabled and booted as normal at 407. In some embodiments, a checkpoint is made at 408. If the checkpoint fails, then secure pre-boot operations are performed at 403. If the checkpoint is successful, then normal boot has completed.
In some embodiments, a firmware attack, firmware update request, or a recovery image update request is detected at 409. For example, the active partition of the I/O hub flash 123 becomes corrupted. This causes a panic condition to be raised and a reboot into the pre-boot stage. If a recovery needs to be made, the security circuitry 105 is engaged to either move the gold image to the active partition (if proper to do so based on a security check), remote toggle a reset, or use a fail-safe radio frequency identification (RFID) device to receive a command.
At 505, the signatures of the firmware in the active partition 203 and recovery partition 205 of the flash 123 and 121 are calculated. The ACM and security circuitry 105 work in conjunction to compute a hash for key verification in most embodiments. The public and private keys discussed above are used for the calculations.
A determination of if the flash recovery partition 205 is valid is made at 507. If yes, the recovery partition 205 is used to restore the active partition 203. If not, then the boot process is halted at 509
A determination of if the active partitions 203 are valid is made at 511. For example, did the keys produce the correct result for the public/private hash calculations. For example, the security circuitry 105 may check to see if there are any pending updates to any of the other firmware components (BMC 119, I/O hub 125, PSU 113, HSBP 115, digital VR 117, etc.). The update candidates (in the temporary partition 207) are verified in some embodiments. In some embodiments, the golden image must also be verified before an update can occur.
When the active partition is valid, a restoration from a recovery partition is made at 513. A recovery policy (such as a number of times recovery should be attempted before declaring that the system is not recoverable due to a potentially spurious reason) is used in some embodiments. Further, boot failure (i.e. failed recovery attempt) is detected either implicitly via digital signature verification or explicitly via boot progress monitoring.
Unfortunately, external intervention is sometimes needed. In some embodiments, a sideband mechanism provides for communication between a platform (e.g., server systems installed in a datacenter) and an external device (e.g., a remote manageability server/console through which the server nodes in the datacenter can be queried or controlled).
A manageability server 621 communicates with an RFID reader 623 to communicate with the RFID tag of a server. In some embodiments, a network of RFID scanners and repeaters is installed within a datacenter. The RFID read ranges are typically designed to be a few centimeters and is confined within the walls of the datacenter. The manageability server 621 executes applications that have the intelligence to control and query the servers 603, 605, 613, and 615. Note that typical components of a server such as a processor and memory are not shown for ease of understanding.
Typically, this approach is very light in terms of a software stack requirements from the server standpoint to establish this communication. This should translate into higher security and reliability of the communications due to less components being involved in the trust boundary of the solution and reduced complexity.
As a result, RFID sideband approach may be used to issue critical commands to a server 603, 605, 613, and 615 in case it fails to make progress without any external intervention. Similarly, the RFID sideband approach may also be used to retrieve error logs and other critical information from the server 603, 605, 613, and 615 in order to determine the state of the server 603, 605, 613, and 615. Thus, it provides the attributes necessary to trigger/force a recovery event of a server 603, 605, 613, and 615 fails to execute an automated recovery as detailed above. Unlike existing BMC based side band methods, this typically uses just auxiliary power to be applied (no core execution required).
This allows for a sideband remote manageability channel via RF. The RFID tag 703 receives encrypted commands with anti-replay protection via an RF input (e.g., 860-960 MHz band). The memory 705 is typically accessible via two interfaces—a wired interface and a wireless RF interface, thus allowing the RFID tag to be used as a mailbox to establish communication between a server and manageability server.
The security circuitry 701 polls the encrypted commands from the memory 705 and decrypts them and takes actions accordingly. Exemplary commands are: enter pre-boot, verify image(s), trigger recovery, reboot, shut down, provide an error log, etc. The received commands may be in a simple format such as a “0” is pre-boot, “1” is verify images, etc. The memory 705 (such as non-volatile random access memory (NVRAM)) may also be used to store a log of errors such that this path also enables the datacenter administrator to securely receive messages from the platform in order to monitor health/status and progress of the platform.
The security circuitry 701 may be the circuitry detailed earlier, or may be other circuitry within a server. Additionally, in some embodiments, software is used instead of dedicated circuitry. The security circuitry 701 includes, or has access to, memory 709 which stores one or more keys and/or integrity check patterns. The security circuitry 701 has the encryption/decryption capabilities to encrypt and decrypt the control/status messages exchanged. Advanced Encryption Standard (AES) encryption is used in some embodiments. In some embodiments, AES Cipher Algorithm in Cipher Block Chaining (CBC) (e.g., AES-CBC 128-bit) encryption is used to establish an encrypted communication link that is protected against anti-replay attacks.
In some embodiments, packets of communication message exchanges between the server and a manageability console are encrypted with anti-replay protection. In some embodiments, AES-CBC-128 encryption is used. A symmetric AES key is pre-provisioned within the security circuitry 701 in the server system (e.g., stored in non-volatile memory 609) as well as within the manageability console.
In some embodiments, the header of the message 811 contains the random number 801 and a command; and the footer of the message 811 contains integrity check pattern 807 and 64 bits of command. When more than 128 bits of command packets are to be used, these additional command packets are included between the header and the footer.
As noted, in some embodiments, AES-CBC encryption is used. As a result, the first 128 bits of the AES encryption affects the next 128-bit pattern. The presence of the random number 801 in the message 811 creates a random string of packets in each message. Upon decryption, a fixed integrity check pattern (stored in, or accessible to, the receiver) is used to check the validity of the message. As such, a valid message upon decryption has an integrity check pattern that matches the integrating check pattern that is stored internally within the security circuitry 701 on the server system as well as the manageability server 621.
Different meanings are associated with single bits or encodings of multiple bits within the command packets of a message to create simple commands. Exemplary commands include, but are not limited to: reboot, shut down, recover platform firmware, enter a pre-boot boot mode, provide error log, etc.
An encrypted string written into a defined location within the RFID tag 703 (e.g., memory 705) and therefore accessible to security circuitry 701 of the target server. In some embodiments, each RFID tag 703 has a unique, or pseudo-unique, identifier that allows independent communication with each server via the unique its identifier.
Commands are typically built and initiated by the manageability server 621, an end-user of the manageability server 621, a server that wants to communicate with the manageability server 621, and/or an end-user of the server that wants to communicate with the manageability server 621.
The random number is placed in front of any command packets of the message at 903. In other words, the random number is the first thing in the message and it is followed by at least one command.
At 905, additional commands (other than the initial command that follows the generated random number) are added to the message.
The packet is closed with an integrity check pattern that is identical to that of the recipient server at 907. The fully assembled message is then encrypted at 909. For example, a message with a random number, followed by 4 commands, followed by an integrity check patter is encrypted using AES-CBC-128 encryption.
A message is retrieved from the mailbox at 1003 and decrypted using a stored key at 1005. A determination of if the message is valid is made at 1007. For example, the integrity check pattern from the decrypted message is matched with the integrity check pattern stored internally. When the message is not valid, then the message is ignored or the server alerts either an end-user or the manageability server of the invalid message.
When the message is valid, the security circuit 701 decodes the commands embedded within the packets and takes appropriate action at 1009. The appropriate action may be an action performed by the security circuit 701, or the security circuit 701 directing another component (e.g., CPU) to perform an action.
In some embodiments, commands require an acknowledgement at 1011. The server typically generates an acknowledgement using one or more aspects of the method of
In some embodiments, when the security circuit 701 is capable of generating a random number, it embeds a new random number in the acknowledgement packet. In some embodiments, when the security circuit 701 cannot generate a random number, it performs a fixed arithmetic operation on the random number from the received message and embeds the resulting number in the acknowledgement packet. The end of the message is tagged with the integrity check pattern of the server. The message is then encrypted message and written back into the mailbox for later retrieval (e.g., by RFID or other means).
The receiving server may perform one more aspects of the above as needed to process the message such as polling, decrypting, determining validity, etc.
Additional embodiments include, but are not limited to an apparatus having a radio frequency identification (RFID) device, the RFID device to include storage to store at least one encrypted sideband message having at least one command, a security circuit coupled to the RFID device, the security circuit to: retrieve at least one encrypted sideband message from the RFID device storage, decrypt the one encrypted sideband message, determine validity of the decrypted sideband message using information from the decrypted sideband message, and perform an action in response to the at least one command. Additionally, one or more of the following applies to an embodiment: the at least one encrypted sideband message is encrypted using advanced encryption standard encryption, the at least one encrypted sideband message is encrypted using advanced encryption standard encryption with cipher block chaining, the information used from the decrypted sideband message to determine validity is an integrity check pattern, the security circuit to compare the integrity check pattern of the decrypted sideband message to an integrity check pattern stored in memory of the security circuit, the integrity check pattern is in a footer portion of the at least one encrypted sideband message, and/or the at least one command is one of: enter pre-boot, verify image, trigger recovery, reboot, shutdown, and provide error log.
Additional embodiments include, but are not limited to a system having manageability server to generate an encrypted sideband message having at least one command, and a server including a radio frequency identification (RFID) device, the RFID device to include storage to store at least one encrypted sideband message having at least one command, a security circuit coupled to the RFID device, the security circuit to: retrieve at least one encrypted sideband message from the RFID device storage, decrypt the one encrypted sideband message, determine validity of the decrypted sideband message using information from the decrypted sideband message, and perform an action in response to the at least one command. Additionally, one or more of the following applies to an embodiment: the at least one encrypted sideband message is encrypted using advanced encryption standard encryption, the at least one encrypted sideband message is encrypted using advanced encryption standard encryption with cipher block chaining, the information used from the decrypted sideband message to determine validity is an integrity check pattern, the security circuit to compare the integrity check pattern of the decrypted sideband message to an integrity check pattern stored in memory of the security circuit, the integrity check pattern is in a footer portion of the at least one encrypted sideband message, and/or the at least one command is one of: enter pre-boot, verify image, trigger recovery, reboot, shutdown, and provide error log.
Additional embodiments include, but are not limited to method comprising generating a random number, placing the generated random number as a first packet of a message, inserting at least one command after the generated random number in the message, closing the message with an integrity check pattern, and encrypting the message for sideband transmission via a radio frequency identification (RFID) device. Additionally, one or more of the following applies to an embodiment: the random number, at least one command, and integrity check pattern are each 64-bit, the integrity check pattern corresponds to an integrity check pattern stored in a recipient device, the at least one command is one of: enter pre-boot, verify image, trigger recovery, reboot, shutdown, and provide error log, the sideband message is encrypted using advanced encryption standard encryption, and/or the sideband message is encrypted using advanced encryption standard encryption with cipher block chaining
The figures detailed below provide exemplary architectures and systems to implement embodiments of the above. In some embodiments, one or more hardware components and/or instructions described above are emulated as detailed below, or implemented as software modules.
Exemplary Register Architecture
Write mask registers 1115—in the embodiment illustrated, there are 8 write mask registers (k0 through k7), each 64 bits in size. In an alternate embodiment, the write mask registers 1115 are 16 bits in size. As previously described, in one embodiment of the invention, the vector mask register k0 cannot be used as a write mask; when the encoding that would normally indicate k0 is used for a write mask, it selects a hardwired write mask of 0xFFFF, effectively disabling write masking for that instruction.
General-purpose registers 1125—in the embodiment illustrated, there are sixteen 64-bit general-purpose registers that are used along with the existing x86 addressing modes to address memory operands. These registers are referenced by the names RAX, RBX, RCX, RDX, RBP, RSI, RDI, RSP, and R8 through R15.
Scalar floating point stack register file (x87 stack) 1145, on which is aliased the MMX packed integer flat register file 1150—in the embodiment illustrated, the x87 stack is an eight-element stack used to perform scalar floating-point operations on 32/64/80-bit floating point data using the x87 instruction set extension; while the MMX registers are used to perform operations on 64-bit packed integer data, as well as to hold operands for some operations performed between the MMX and XMM registers.
Alternative embodiments of the invention may use wider or narrower registers. Additionally, alternative embodiments of the invention may use more, less, or different register files and registers.
Exemplary Core Architectures, Processors, and Computer Architectures
Processor cores may be implemented in different ways, for different purposes, and in different processors. For instance, implementations of such cores may include: 1) a general purpose in-order core intended for general-purpose computing; 2) a high performance general purpose out-of-order core intended for general-purpose computing; 3) a special purpose core intended primarily for graphics and/or scientific (throughput) computing. Implementations of different processors may include: 1) a CPU including one or more general purpose in-order cores intended for general-purpose computing and/or one or more general purpose out-of-order cores intended for general-purpose computing; and 2) a coprocessor including one or more special purpose cores intended primarily for graphics and/or scientific (throughput). Such different processors lead to different computer system architectures, which may include: 1) the coprocessor on a separate chip from the CPU; 2) the coprocessor on a separate die in the same package as a CPU; 3) the coprocessor on the same die as a CPU (in which case, such a coprocessor is sometimes referred to as special purpose logic, such as integrated graphics and/or scientific (throughput) logic, or as special purpose cores); and 4) a system on a chip that may include on the same die the described CPU (sometimes referred to as the application core(s) or application processor(s)), the above described coprocessor, and additional functionality. Exemplary core architectures are described next, followed by descriptions of exemplary processors and computer architectures.
Exemplary Core Architectures
In-Order and Out-of-Order Core Block Diagram
In
The front end unit 1230 includes a branch prediction unit 1232 coupled to an instruction cache unit 1234, which is coupled to an instruction translation lookaside buffer (TLB) 1236, which is coupled to an instruction fetch unit 1238, which is coupled to a decode unit 1240. The decode unit 1240 (or decoder) may decode instructions, and generate as an output one or more micro-operations, micro-code entry points, microinstructions, other instructions, or other control signals, which are decoded from, or which otherwise reflect, or are derived from, the original instructions. The decode unit 1240 may be implemented using various different mechanisms. Examples of suitable mechanisms include, but are not limited to, look-up tables, hardware implementations, programmable logic arrays (PLAs), microcode read only memories (ROMs), etc. In one embodiment, the core 1290 includes a microcode ROM or other medium that stores microcode for certain macroinstructions (e.g., in decode unit 1240 or otherwise within the front end unit 1230). The decode unit 1240 is coupled to a rename/allocator unit 1252 in the execution engine unit 1250.
The execution engine unit 1250 includes the rename/allocator unit 1252 coupled to a retirement unit 1254 and a set of one or more scheduler unit(s) 1256. The scheduler unit(s) 1256 represents any number of different schedulers, including reservations stations, central instruction window, etc. The scheduler unit(s) 1256 is coupled to the physical register file(s) unit(s) 1258. Each of the physical register file(s) units 1258 represents one or more physical register files, different ones of which store one or more different data types, such as scalar integer, scalar floating point, packed integer, packed floating point, vector integer, vector floating point, status (e.g., an instruction pointer that is the address of the next instruction to be executed), etc. In one embodiment, the physical register file(s) unit 1258 comprises a vector registers unit, a write mask registers unit, and a scalar registers unit. These register units may provide architectural vector registers, vector mask registers, and general purpose registers. The physical register file(s) unit(s) 1258 is overlapped by the retirement unit 1254 to illustrate various ways in which register renaming and out-of-order execution may be implemented (e.g., using a reorder buffer(s) and a retirement register file(s); using a future file(s), a history buffer(s), and a retirement register file(s); using a register maps and a pool of registers; etc.). The retirement unit 1254 and the physical register file(s) unit(s) 1258 are coupled to the execution cluster(s) 1260. The execution cluster(s) 1260 includes a set of one or more execution units 1262 and a set of one or more memory access units 1264. The execution units 1262 may perform various operations (e.g., shifts, addition, subtraction, multiplication) and on various types of data (e.g., scalar floating point, packed integer, packed floating point, vector integer, vector floating point). While some embodiments may include a number of execution units dedicated to specific functions or sets of functions, other embodiments may include only one execution unit or multiple execution units that all perform all functions. The scheduler unit(s) 1256, physical register file(s) unit(s) 1258, and execution cluster(s) 1260 are shown as being possibly plural because certain embodiments create separate pipelines for certain types of data/operations (e.g., a scalar integer pipeline, a scalar floating point/packed integer/packed floating point/vector integer/vector floating point pipeline, and/or a memory access pipeline that each have their own scheduler unit, physical register file(s) unit, and/or execution cluster—and in the case of a separate memory access pipeline, certain embodiments are implemented in which only the execution cluster of this pipeline has the memory access unit(s) 1264). It should also be understood that where separate pipelines are used, one or more of these pipelines may be out-of-order issue/execution and the rest in-order.
The set of memory access units 1264 is coupled to the memory unit 1270, which includes a data TLB unit 1272 coupled to a data cache unit 1274 coupled to a level 2 (L2) cache unit 1276. In one exemplary embodiment, the memory access units 1264 may include a load unit, a store address unit, and a store data unit, each of which is coupled to the data TLB unit 1272 in the memory unit 1270. The instruction cache unit 1234 is further coupled to a level 2 (L2) cache unit 1276 in the memory unit 1270. The L2 cache unit 1276 is coupled to one or more other levels of cache and eventually to a main memory.
By way of example, the exemplary register renaming, out-of-order issue/execution core architecture may implement the pipeline 1200 as follows: 1) the instruction fetch 1238 performs the fetch and length decoding stages 1202 and 1204; 2) the decode unit 1240 performs the decode stage 1206; 3) the rename/allocator unit 1252 performs the allocation stage 1208 and renaming stage 1210; 4) the scheduler unit(s) 1256 performs the schedule stage 1212; 5) the physical register file(s) unit(s) 1258 and the memory unit 1270 perform the register read/memory read stage 1214; the execution cluster 1260 perform the execute stage 1216; 6) the memory unit 1270 and the physical register file(s) unit(s) 1258 perform the write back/memory write stage 1218; 7) various units may be involved in the exception handling stage 1222; and 8) the retirement unit 1254 and the physical register file(s) unit(s) 1258 perform the commit stage 1224.
The core 1290 may support one or more instructions sets (e.g., the x86 instruction set (with some extensions that have been added with newer versions); the MIPS instruction set of MIPS Technologies of Sunnyvale, Calif.; the ARM instruction set (with optional additional extensions such as NEON) of ARM Holdings of Sunnyvale, Calif.), including the instruction(s) described herein. In one embodiment, the core 1290 includes logic to support a packed data instruction set extension (e.g., AVX1, AVX2), thereby allowing the operations used by many multimedia applications to be performed using packed data.
It should be understood that the core may support multithreading (executing two or more parallel sets of operations or threads), and may do so in a variety of ways including time sliced multithreading, simultaneous multithreading (where a single physical core provides a logical core for each of the threads that physical core is simultaneously multithreading), or a combination thereof (e.g., time sliced fetching and decoding and simultaneous multithreading thereafter such as in the Intel® Hyperthreading technology).
While register renaming is described in the context of out-of-order execution, it should be understood that register renaming may be used in an in-order architecture. While the illustrated embodiment of the processor also includes separate instruction and data cache units 1234/1274 and a shared L2 cache unit 1276, alternative embodiments may have a single internal cache for both instructions and data, such as, for example, a Level 1 (L1) internal cache, or multiple levels of internal cache. In some embodiments, the system may include a combination of an internal cache and an external cache that is external to the core and/or the processor. Alternatively, all of the cache may be external to the core and/or the processor.
Specific Exemplary In-Order Core Architecture
The local subset of the L2 cache 1304 is part of a global L2 cache that is divided into separate local subsets, one per processor core. Each processor core has a direct access path to its own local subset of the L2 cache 1304. Data read by a processor core is stored in its L2 cache subset 1304 and can be accessed quickly, in parallel with other processor cores accessing their own local L2 cache subsets. Data written by a processor core is stored in its own L2 cache subset 1304 and is flushed from other subsets, if necessary. The ring network ensures coherency for shared data. The ring network is bi-directional to allow agents such as processor cores, L2 caches and other logic blocks to communicate with each other within the chip. Each ring data-path is 1012-bits wide per direction.
Thus, different implementations of the processor 1400 may include: 1) a CPU with the special purpose logic 1408 being integrated graphics and/or scientific (throughput) logic (which may include one or more cores), and the cores 1402A-N being one or more general purpose cores (e.g., general purpose in-order cores, general purpose out-of-order cores, a combination of the two); 2) a coprocessor with the cores 1402A-N being a large number of special purpose cores intended primarily for graphics and/or scientific (throughput); and 3) a coprocessor with the cores 1402A-N being a large number of general purpose in-order cores. Thus, the processor 1400 may be a general-purpose processor, coprocessor or special-purpose processor, such as, for example, a network or communication processor, compression engine, graphics processor, GPGPU (general purpose graphics processing unit), a high-throughput many integrated core (MIC) coprocessor (including 30 or more cores), embedded processor, or the like. The processor may be implemented on one or more chips. The processor 1400 may be a part of and/or may be implemented on one or more substrates using any of a number of process technologies, such as, for example, BiCMOS, CMOS, or NMOS.
The memory hierarchy includes one or more levels of cache 1404A-N within the cores, a set or one or more shared cache units 1406, and external memory (not shown) coupled to the set of integrated memory controller units 1414. The set of shared cache units 1406 may include one or more mid-level caches, such as level 2 (L2), level 3 (L3), level 4 (L4), or other levels of cache, a last level cache (LLC), and/or combinations thereof. While in one embodiment a ring based interconnect unit 1412 interconnects the integrated graphics logic 1408, the set of shared cache units 1406, and the system agent unit 1410/integrated memory controller unit(s) 1414, alternative embodiments may use any number of well-known techniques for interconnecting such units. In one embodiment, coherency is maintained between one or more cache units 1406 and cores 1402-A-N.
In some embodiments, one or more of the cores 1402A-N are capable of multi-threading. The system agent 1410 includes those components coordinating and operating cores 1402A-N. The system agent unit 1410 may include for example a power control unit (PCU) and a display unit. The PCU may be or include logic and components needed for regulating the power state of the cores 1402A-N and the integrated graphics logic 1408. The display unit is for driving one or more externally connected displays.
The cores 1402A-N may be homogenous or heterogeneous in terms of architecture instruction set; that is, two or more of the cores 1402A-N may be capable of execution the same instruction set, while others may be capable of executing only a subset of that instruction set or a different instruction set.
Exemplary Computer Architectures
Referring now to
The optional nature of additional processors 1515 is denoted in
The memory 1540 may be, for example, dynamic random access memory (DRAM), phase change memory (PCM), or a combination of the two. For at least one embodiment, the controller hub 1520 communicates with the processor(s) 1510, 1515 via a multi-drop bus, such as a frontside bus (FSB), point-to-point interface such as QuickPath Interconnect (QPI), or similar connection 1595.
In one embodiment, the coprocessor 1545 is a special-purpose processor, such as, for example, a high-throughput MIC processor, a network or communication processor, compression engine, graphics processor, GPGPU, embedded processor, or the like. In one embodiment, controller hub 1520 may include an integrated graphics accelerator.
There can be a variety of differences between the physical resources 1510, 1515 in terms of a spectrum of metrics of merit including architectural, microarchitectural, thermal, power consumption characteristics, and the like.
In one embodiment, the processor 1510 executes instructions that control data processing operations of a general type. Embedded within the instructions may be coprocessor instructions. The processor 1510 recognizes these coprocessor instructions as being of a type that should be executed by the attached coprocessor 1545. Accordingly, the processor 1510 issues these coprocessor instructions (or control signals representing coprocessor instructions) on a coprocessor bus or other interconnect, to coprocessor 1545. Coprocessor(s) 1545 accept and execute the received coprocessor instructions.
Referring now to
Processors 1670 and 1680 are shown including integrated memory controller (IMC) units 1672 and 1682, respectively. Processor 1670 also includes as part of its bus controller units point-to-point (P-P) interfaces 1676 and 1678; similarly, second processor 1680 includes P-P interfaces 1686 and 1688. Processors 1670, 1680 may exchange information via a point-to-point (P-P) interface 1650 using P-P interface circuits 1678, 1688. As shown in
Processors 1670, 1680 may each exchange information with a chipset 1690 via individual P-P interfaces 1652, 1654 using point to point interface circuits 1676, 1694, 1686, 1698. Chipset 1690 may optionally exchange information with the coprocessor 1638 via a high-performance interface 1692. In one embodiment, the coprocessor 1638 is a special-purpose processor, such as, for example, a high-throughput MIC processor, a network or communication processor, compression engine, graphics processor, GPGPU, embedded processor, or the like.
A shared cache (not shown) may be included in either processor or outside of both processors, yet connected with the processors via P-P interconnect, such that either or both processors' local cache information may be stored in the shared cache if a processor is placed into a low power mode.
Chipset 1690 may be coupled to a first bus 1616 via an interface 1696. In one embodiment, first bus 1616 may be a Peripheral Component Interconnect (PCI) bus, or a bus such as a PCI Express bus or another third generation I/O interconnect bus, although the scope of the present invention is not so limited.
As shown in
Referring now to
Referring now to
Embodiments of the mechanisms disclosed herein may be implemented in hardware, software, firmware, or a combination of such implementation approaches. Embodiments of the invention may be implemented as computer programs or program code executing on programmable systems comprising at least one processor, a storage system (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device.
Program code, such as code 1630 illustrated in
The program code may be implemented in a high level procedural or object oriented programming language to communicate with a processing system. The program code may also be implemented in assembly or machine language, if desired. In fact, the mechanisms described herein are not limited in scope to any particular programming language. In any case, the language may be a compiled or interpreted language.
One or more aspects of at least one embodiment may be implemented by representative instructions stored on a machine-readable medium which represents various logic within the processor, which when read by a machine causes the machine to fabricate logic to perform the techniques described herein. Such representations, known as “IP cores” may be stored on a tangible, machine readable medium and supplied to various customers or manufacturing facilities to load into the fabrication machines that actually make the logic or processor.
Such machine-readable storage media may include, without limitation, non-transitory, tangible arrangements of articles manufactured or formed by a machine or device, including storage media such as hard disks, any other type of disk including floppy disks, optical disks, compact disk read-only memories (CD-ROMs), compact disk rewritable's (CD-RWs), and magneto-optical disks, semiconductor devices such as read-only memories (ROMs), random access memories (RAMS) such as dynamic random access memories (DRAMs), static random access memories (SRAMs), erasable programmable read-only memories (EPROMs), flash memories, electrically erasable programmable read-only memories (EEPROMs), phase change memory (PCM), magnetic or optical cards, or any other type of media suitable for storing electronic instructions.
Accordingly, embodiments of the invention also include non-transitory, tangible machine-readable media containing instructions or containing design data, such as Hardware Description Language (HDL), which defines structures, circuits, apparatuses, processors and/or system features described herein. Such embodiments may also be referred to as program products.
Emulation (including binary translation, code morphing, etc.)
In some cases, an instruction converter may be used to convert an instruction from a source instruction set to a target instruction set. For example, the instruction converter may translate (e.g., using static binary translation, dynamic binary translation including dynamic compilation), morph, emulate, or otherwise convert an instruction to one or more other instructions to be processed by the core. The instruction converter may be implemented in software, hardware, firmware, or a combination thereof. The instruction converter may be on processor, off processor, or part on and part off processor.